The Optimized Design And Performance Analysis Of An Evaporation System Of Solutions With High Boiling Point Elevation

Mechanical Vapor Recompression(MVR)is an efficient energy-saving method,which replaces the steam with the energy consumed by the compressor,and makes use of the latent heat of the secondary steam during the evaporation process.It achieves its energy recycling,thereby reducing the energy consumption of the evaporation process.This article is about the evaporation and concentration process of the high boiling point solution,based on the actual working capacity of the steam compressor,the method of hierarchical compression MVR evaporation system for the high boiling point solution was proposed in order to reduce the energy consumption,and analyzed in thermodynamics.On this basis,the whole system is optimized to find the best operating conditions and make comprehensive performance evaluation of the entire system.Finally,the experimental device of hierarchical compression MVR evaporative system is designed.The characteristics of the evaporation process of high boiling point solution were analyzed.Based on the actual working capacity of steam compressors,the calculation model of hierarchical compression MVR evaporation system for high boiling point solution was designed.The main equipment calculation model was established by means of chemical process steady state simulation software Aspen and verified the platform with the pilot experiment data.The performance and energy efficiency of the hierarchical compression MVR evaporative system proposed in this paper are improved obviously by using the full-pressure series MVR evaporation system as the reference scheme and the thermodynamic performance parameters of the two systems are obtained.Under the best operating conditions when the compression ratio of the steam compressor is 2.0 and the concentration of the primary discharge is 0.23,the hierarchical compression MVR evaporation system compared to multistage compression MVR evaporation system can save 47.83% of the system energy consumption and 28.75% of the equipment cost.And the influence of operating parameters such as the compression ratio of the steam compressor and the concentration of the primary discharge on the MVR evaporation system was analyzed.Based on the simulation process of the hierarchical compression MVR evaporation system,the model of the hierarchical compression MVR evaporation system considering the influence of the actual composition of the solution is established,the distribution of the loss of the hierarchical compression MVR evaporation system is obtained,and the operating parameters such as steam compressor compression ratio,the concentration of a discharge of the system on the efficiency of the system.The results show that the efficiency of the graded compression MVR evaporation system is about 7.93%,and the primary steam compressor and evaporator are the main link of the system loss,accounting for 26.7% and 68.96% of the total loss of the system.Finally,the experimental device of hierarchical compression MVR evaporation system suitable for the evaporation and concentration process of high boiling point solution is designed.The steam compressor adopts Roots type steam compressor and evaporator adopts falling film evaporator.In this paper,the hierarchical compression MVR evaporation system based on the actual working capacity of steam compressors is suitable for the evaporation,concentration and crystallization of high boiling point solutions,which extends the application range of MVR and provides a way of thinking and method for reducing the energy consumption of the evaporation process unit.The thermodynamic performance parameters of the hierarchical compression MVR evaporation system provide a theoretical reference for the engineering application of the hierarchical compression MVR evaporation system.